Manufacture of wrought-iron



1 f I UNITED. STATES PATENTOFFICE.

Lucius D. OHAPIN, on CHICAGO, ILLINOIS.

MANUFACTURE WROUGHT-l RON.

SPECIFICATION formingpart of Letters Patent No. 2s3,o74, dated August 14, 1883,

Application filed October 3, 1881. (No specimens.)

To all whom it may concern:

Be it known that I, LUoIUs D. CHAPIN, a

citizen of the United States, residing at Ohiuse the same.

cago, in the county of Cook and State of Illinois, have invented certain new and useful Imwhich said invention appertains to make and In themanufacture ofwrought-iron as ordinarily practiced the chargeof cast-iron is subjected tothe reducing action of the furnace gases on areverberatory hearth having a fix or fettle? made up in considerable measure of iron oxide, either in the formof ore or of mill-cinder, scale, or the like. The presence of the oxide lining is deemed highly essential to the successful working of the charge, for,

without it whenthe metal comes to nature and is in pasty condition ready to be collected into a ball or loop, the wrought-iron adheres tenaciously to the silicious lining, thus making it extremely difficult to work into a mass, and then onlyat a great loss of the metal. Hence it is that to avoid the difficulty precaution is' taken to supplement the usual lining with charges of iron oxide in various forms j and combinations spread ,upon the hearth above the same and next in contact with the molten metal. Practicehas demonstrated that in this way the cast metal may be reduced to wrought-iron with entire economy, save that after each heat, or at best after very few heats, it is necessary to renew the iron-oxide lining, which not onlycons umes time in bringing the furnace again into condition, but is wasteful, moreover, of crude materials rich in iron.

The present invention has for its object to avoid this repeated andnecessarily expensive renewal of the oxide lining in manufacture of wrought-iron, and is based upon the dis covery that, if the crude cast-iron be subjected to a' preliminary treatment in a pneumatic converter having the usual lining of fire-brick,

ganister, or like silicious material until said cast-iron is practically free from silicon anda large per centum of its carbon, the iron may then be transferred to a reverberatory hearth having an iron-oxide lining, and therein speedily reduced to a wrought condition without material loss of oxidelimng, and consequently without the frequent renewal of said lining which the methods of manufacture heretofore in vogue have made necessary.

In Letters Patent granted to me January 13, 1880, No. 223,481, I have described and claimed a process or method of making wrought-ironwherein the molten metal, while inclosedin a converter, was subjected simul taneously to the oscillatory or rotary action of the converter and to the action of anair-blast untilit approaches nature, with an occasional sembles the lining, fix, orfettling usually employed in puddling or boiling furnaces. Such linings have usually a considerable percentage of oxide of iron or other metallic elements, which are supposed to nourish the iron under treatment and to facilitate its coming to nature. It was with reference to the use of linings of that general class that I described the oscillatory or rotary motion of the con verter more or less intermittently as an ele- -ment of the invention set forth in said patent.

If, instead of said non-refractory linings having a considerablepercentage of iron oxide or other metallic elements in their composition, the lining of theconverterbe of fire-brick, ganister, or like silicious material, I have found, first,- that it is unnecessaryto impart to the converter any. oscillatory or rotary motion during the first stage of the process; second, that in subjecting the molten metal to the action of. the airblast alone for a few minutes until it more gree of conversion corresponding thereto, the refractory lining is attacked but slightly, and,

or less approaches nature or comes to a dc IOO indeed, very. much less than when a nonrefractory lining is employed, as specified, thus saving the expense of frequent renewal; while, third, the ironis left in such purified condition that, upon subsequent transfer to a baller having a metallic lining usual to a puddling, balling, or Danks furnace, it can be speedily reduced therein to a wrought condition under influence of a reverberatory flame with practicallylittle or none of the disastrous cutting of the lining which has been heretofore experienced.

' In the practice of my present invention I use for a converter a horizontal cylindrical chamber-such as is called for in said Patent No. 223,481-ha ving an air-blast or an ordinary Bessemer converter, or any other desired form of chamber suitable for the purpose, but having an air-blast such, or substantially such, as the Bessemer operation calls for. Such con verter may be mounted upon trunnions for convenience in charging and removing the charge, or it may be fixed in position andprovlded with a charging-hole and tap-hole, as such devices are known in the art. The converter is to be lined with ganister or fire-clay or other suitable refractory material, and especially excluding any such percentage of metallic oxide as is usually employed in the Danks or in ordinary puddling or boiling furnaces.

The charge of metal may be run in from a cupola or blast furnace, and then treated with the air-blast substantially as describedin said Patent No. 223,481, except that the converter need not be rotated or oscillated during the blowing of the blast, nor need the metal have any other motion imparted to it than what results from the blowing of the blast. The blast is kept blowing for a short time-say, for ten minutes, more or lesseither till the metal approaches nature or comes to or approaches a I until the objectionable impurities which the air-blast is adapted to remove shall have been substantially eliminated, or so far eliminated that the presence of the residue will not in subsequent working prevent the production of good iron; The, metal is next tapped, run or otherwise transferred to a baller or balling chamber having any lining such as is adapted to nourish the iron or aid in fluxing or decarbonizing or otherwise completing its conversion and bringingit completely'to nature, and such baller or balling-chamber may be of any construction and operation, provided, only, it be of such as to admit of the use of a reverberatory heat or. flame on the iron under treatment therein, and also permit the use of motion imparted mechanically to the iron,preferably by the rotary or oscillatory motion of the baller or balling-chamber itself. The inc-- chanical work of balling the iron under such conditions and of removing the ball and further working it is so well known in the art that further description is unnecessary.

In practice of the process as above described I have found that the quality of the iron is materially improved that the labor and expense of its production is much lessened by doing away with the constant repairs to the converter-lining made necessary when this was of nonrefractory materials, and that by the subsequent transfer of the metal to the baller after the first part of the process of conversion car-' ried on in the converter has been finished the lining of the baller is slightly, if at all, im paired, or, if impaired, is replenished as much, or nearly as much, as it is worn away, and thus becomes practically selfsustaining. This is a great economy as compared with any process with which I am familiar. The whole expense, or nearly so, of fix or fettling is avoided in the baller when once lined,while the refractory lining of the converter is very permanent as compared with the lining of an ordinary puddling or'boiling or Danks furnace.

By the foregoing treatment the molten charge of iron as it leaves the converter is so far advanced to a wrought condition that only a few minutes exposure in the balling-chamber is necessary to perfect the reduction and allow for the formation of the loop. It is plain that the process as defined is very expeditious in comparison with the older methods of making wrought-iron, and has, besides, the merit of working upon large masses of metal, insuring greater homogeneity for a larger product.

Prior to the invention it has been proposed I to partially decarburize and desiliconize a charge of molten cast-iron by an oxidizingblast in a pneumatic converter, and thereafter to transfer the metal to an open hearth having a refractory lining of sand, fire-clay, ganister, or the like, wherein it is subjected to a reverberatory flame and to the actions of titanifer- 'ous-iron oxide and basic fluoride additions in conjunction; but thesematerials are designed to free the iron of its phosphorus and sulphur, requires several hours to perfect their action, the metal is in molten condition throughout, and is finally cast in ingots and not reduced to a puddled ball, as herein defined. The product thus obtained is somewhat malleable, but is in no sense wrought-iron, nor does its course of treatment give any clue to the conditions under which wrought-iron may be produced.

Having thus described the invention, what I claim as new, and desire to secure by Letters Patent, is a 1. The process of making wrought iron which consists in subjecting molten cast-iron, in a Bessemer converter having a fire-brick, ganister, or like silicious lining to the action of an air-blast until the objectionable impurities, which the air-blast is adapted to remove, shall have been substantially eliminated, and then transferring the metal to a separate furnace or ballingchamber haying essentially an oXide-of-iron lining, and therein subjecting it to reverberatory flame and to puddling action until it is reduced to a wrought condition to form a ball or loop, substantially as described. 2. The process of making Wrought iron which consists in subjecting molten cast-iron, in a Bessemer converter having a refractory lining to the action .of an air-blast until the objectionable impurities, which the air-blast is adapted to remove, shall have been substantially eliminated and then transferring the metal to a separate furnace or chamber, and therein subjecting it to a reverberatory flame and to a rotary puddling action until it is re- 15 duced to a Wrought condition to form a ball or loop, substantially as described. i I11 testimony whereof I have hereunto set my hand.

y LU-OIUS n; OHAJPIN.

Witnesses:

M. T. HUGGINs, M. F. 'GHAPIN. 

